sony-vaio-z-series team mailing list archive

[Adam Hill <sidepipeuk@xxxxxxxxx>]

> This is interesting, so that would mean that the "physical connection" of
> the Intel card to the backlight is in fact *not* physical at all, but
> instead it's a software situation that results from the BIOS's way of
> initializing things ?

	Ahh, no, I don't believe so. The reason that I say this is that we use 
either a modified BIOS to enable static switching, or the old kernel boot 
trick, in order to get the Vaio to initialise the NVidia card and disable the 
Intel card completely in order to get the NVidia drivers to work. If the link 
to brightness was configurable, then it would seem strange that Sony added 
these options in the BIOS, but then didn't link the brightness to the NVidia 
card at the same time!

> It would be really, really great to be able to fix the mapping, so that the
> NVIDIA card can then control everything.  I'm pretty damn sure this is just
> a matter of getting more exposure (ie: more knowledgable kernel and/or
> "Nouveau" developers) about this issue, what do you think ?

	Well, what it needs is someone who really knows how VGA cards work in 
terms of initial set-up by the BIOS. We could then "undo" what was done for 
the Intel card and re-do what the BIOS does in static mode for the NVIdia.

	Moving on from that, if X has a way of saving a session ( well, window 
posisions and screen content in a way that is independent of VRAM, ) then we 
could even have dynamic switching working, i.e.

Save session state and exit X.
Unmap Intel card
Remap NVidia
Run X with restored session.

	Unfortunately I don't have this knowledge or the time to acquire it :(.

Adam.

 
> On Fri, Dec 10, 2010 at 10:12 AM, Adam Hill <sidepipeuk@xxxxxxxxx> wrote:
> > > Same here, I would be very happy if we could control brightness while
> > > running on the NVIDIA card.  I don't know exactly what it takes, maybe
> > 
> > the
> > 
> > > Intel card needs to be accessible from the PCI bus (since, as I heard,
> > 
> > the
> > 
> > > physical brightless control is connected to the Intel card).  As I see
> > 
> > it,
> > 
> > > initializing the Intel card without allocating any of its buffers (ie:
> > > initialize it just enough so we can ask it to set the brightness) might
> > 
> > be
> > 
> > > the way to do it.
> > > 
> >         I fear that it may be much more complicated than that because as
> > 
> > far as I
> > know the BIOS initialises the Intel card at boot time regardless of the
> > position of the hybrid graphics switch. That means that by the time the
> > Linux
> > kernel starts the Intel card already has its BIOS and VRAM mapped in to
> > where
> > the NVidia drivers expect their stuff to be.
> > 
> >        The simplest solution overall would be if Sony modified the BIOS
> >        to
> > 
> > initialise the correct card at first boot, but that isn't going to happen
> > because Windows doesn't care. So, the two sensible options would seem to
> > be:
> > 
> > 1) Unmap the Intel card's resources and map in the NVidia card before the
> > NVidia module is loaded.
> > 
> > 2) Somehow map both cards in. I'm not sure if this is possible because I
> > don't
> > really know much about how video BIOS is accessed - if it is expected to
> > be in
> > a particular place in the memory map then this would be impossible.
> > 
> > Adam.
> > 
> > > Maybe we could set up a bounty that would go to the one who publishes a
> > > kernel patch and/or generic shell script and instructions to do it ?
> >  
> >  That
> >  
> > > could be nice...
> > > 
> > > On Thu, Dec 9, 2010 at 5:36 PM, Jordi Augé <jordi@xxxxxxxx> wrote:
> > > > Hi,
> > > > 
> > > > I'm a new Vaio Z user, and I've successfully installed Linux as Main
> > > > OS on a VPCZ11X9/e, after some struggling I've gotten everything
> > > > working, including hsdpa and graphics switching. My only gripe so
> > > > far is the inability to control screen brightness when using nvidia
> > > > graphics.
> > > > 
> > > > Any updates on this issue? what changes will be necessary to
> > > > implement it?
> > > > 
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